using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Net;
using HtmlAgilityPack;
using System.IO;

namespace mlpreactor
{
    class Program
    {
        static void Main(string[] args)
        {
            ServicePointManager.DefaultConnectionLimit = 10000;
            Console.Write("1. Скачать все картинки\n2. Скачивать по тегам(теги разделяются пробелом)\n\n>Выбор: ");
            int choice = int.Parse(Console.ReadLine());
            Console.Clear();

            if (choice == 1)
            {
                Directory.CreateDirectory("images");
                int maxPage = int.Parse(getMaxPage("http://mlp.reactor.cc/"));

                for (int i = maxPage; i > 1; i--)
                {
                    Console.WriteLine(">парсим страницу: " + "http://mlp.reactor.cc/" + i);
                    var pictures = getPictureList("http://mlp.reactor.cc/" + i);
                    Parallel.ForEach(pictures, pic =>
                    {
                        var client = new WebClient();
                        client.DownloadFile(pic, Path.Combine(Directory.GetCurrentDirectory(), "images", pic.Substring(pic.LastIndexOf('-') + 1)));
                    });

                }
            }

            else
            {
                Console.Write(">тег: ");
                string tag = Console.ReadLine();
                Console.Clear();
                Directory.CreateDirectory(tag);
                string encoded = tag.Replace(" ", "%2B");
                int maxPage = int.Parse(getMaxPage("http://mlp.reactor.cc/tag/" + encoded));

                for (int i = maxPage; i > 1; i--)
                {
                    Console.WriteLine(">парсим страницу: " + "http://mlp.reactor.cc/tag/" + encoded + "/" + i);
                    var pictures = getPictureList("http://mlp.reactor.cc/tag/" + encoded + "/" + i);
                    Parallel.ForEach(pictures, pic =>
                        {
                            var client = new WebClient();
                            client.DownloadFile(pic, Path.Combine(Directory.GetCurrentDirectory(), tag, pic.Substring(pic.LastIndexOf('-') + 1)));
                        });
                }
            }
        }

        private static string getMaxPage(string url)
        {
            HttpWebRequest req = (HttpWebRequest)WebRequest.Create(url);
            Stream stream = req.GetResponse().GetResponseStream();
            StreamReader reader = new StreamReader(stream);
            string html = reader.ReadToEnd();
            HtmlDocument doc = new HtmlDocument();
            doc.LoadHtml(html);
            string page = doc.DocumentNode.SelectSingleNode("//./a[@class='next']").Attributes["href"].Value;

            return page.Substring(page.LastIndexOf(@"/") + 1);
        }

        private static List<string> getPictureList(string url)
        {
            List<string> pictures = new List<string>();
            HttpWebRequest req = (HttpWebRequest)WebRequest.Create(url);
            Stream stream = req.GetResponse().GetResponseStream();
            StreamReader reader = new StreamReader(stream);
            string html = reader.ReadToEnd();
            HtmlDocument doc = new HtmlDocument();
            doc.LoadHtml(html);

            //full-size
            if (html.Contains("prettyPhotoLink"))
            {
                var fullSz = doc.DocumentNode.SelectNodes("//./div[@class='image']/a");
                foreach (var div in fullSz)
                    pictures.Add(div.Attributes["href"].Value);

            }

            else
            {
                var stdSz = doc.DocumentNode.SelectNodes("//./div[@class='image']//./img");
                foreach (var div in stdSz)
                    pictures.Add(div.Attributes["src"].Value);
            }

            return pictures;
        }
    }
}